Virginia Gov. Bob McDonnell, chairman of the Republican Governors Association, said Wednesday that he will fly to Florida this weekend to campaign for presidential hopeful Mitt Romney.

Governor Robert F. McDonnell participates in the 47th Annual Commonwealth Prayer Breakfast at the Richmond Convention Center on Jan. 11, 2012. (Photo by Tracy A. Woodward/The Washington Post)

McDonnell endorsed Romney Friday and spent a day campaigning for him in South Carolina, where the former Massachusetts governor came in a disappointing second. He won New Hampshire and lost Iowa, but only by 34 votes.

“We’re only three primaries in,’’ McDonnell said. “He tied one. He won one and had a disappointment in South Carolina. This is a big race. This is a big primary — Florida — and it’s clearly turned into a very competitive race. It looks like at about dead heat right now and the super PACs are doing their thing and a lot of messaging is going on about the liabilities of the other candidates.”

McDonnell, one of the most popular governors in America and someone mentioned as a possible vice presidential candidate, had said for months that he preferred to back a governor or former governor. Romney became the last governor in the race after Texas Gov. Rick Perry, a friend of McDonnell’s, dropped out last week.

Romney, the national front-runner for the Republican presidential nomination, has been in Virginia several times this cycle for fundraisers and to campaign for legislative candidates last year.

“I think it’ll be competitive,’’ McDonnell said of Florida primary. “I think Governor Romney has and still considered the front runner but I don’t think any one ever thought this would be a cake walk. You’ve got some very talented people on that stage — Newt Gingrich and Rick Santorum in particular.”

Only Romney and Rep. Ron Paul (Tex.) will appear on the Virginia primary ballot March 6. The other candidates — former House speaker Newt Gingrich and former senator Rick Santorum (Pa.) — did not qualify.

Romney has already announced a leadership team in Virginia, led by Lt. Gov. Bill Bolling. He also has support from former governor James Gilmore and several legislators. Attorney General Ken Cuccinelli has stayed out of the race.